Patella Luxation (dislocation)

Dislocation of the patella

What is patella luxation?

Patella luxation is the dislocation of the patella bone. The normal patella runs in an up and down direction within a groove on the thigh bone. A luxating patella can slip in and out of its normal position in the patella groove. Patella luxation is an extremely common condition in young small breed dogs such as Poodles, Pomeranians, and Shih Tzus, and occurs occasionally in large breed dogs.

What causes patella luxation?

It is a congenital problem that is caused by the abnormal alignment of the patella tendon, usually towards the inside of the leg. The problem can get worse as the dog grows.

What are the signs and symptoms?

You will typically notice an occasional skipping step in your dog’s stride, or you will notice that your pet may be favouring a leg. Often the patella will spontaneously slip back into place and the dog will then walk normally as if nothing has happened.

As the dog grows, the condition may get worse and they will limp or skip more often.

When the patella slips in and out of its normal position, the joint capsule becomes stretched and damaged. This causes pain and inflammation and can lead to early arthritis.

How do we treat patella luxation?

Treatment of a pet with a luxating patella is dependent upon the severity of the condition. There are 4 grades of patella luxation:

Grade 1

Luxation with manual pressure – usually not painful. Grade 1 luxations usually do not require any specific treatment but do need to be monitored for worsening. Sometimes pain medication is required.

Grade 2

Patella luxation with flexion and extension of the knee but returns to the groove on its own – occasional pain is present.

Grade 3

Luxation with flexion and extension and returns to the groove with manual reduction – considerable pain and lameness (limping). Grade 2 and 3 luxations usually benefit from surgical correction – this involves realignment of the patella tendon and deepening of the groove the patella sits in.

Grade 4

What happens if my pet is ineligible for surgery?

Dogs with grade 2 to 4 luxations will experience pain occasionally to persistently depending upon the severity. Dogs with patella luxation are more prone to injuring their ligaments as they get older. Having a patella that slips in and out will cause arthritis – a painful and progressive problem. Speak to your local Greencross Vets for a treatment or pain management plan.